1. Field of the Invention
The present invention relates to a semiconductor hermetically sealed package.
2. Background Art
In semiconductor hermetically sealed packages, a semiconductor element is mounted in a package and then a lid is seam-welded to secure air tightness. The package and the lid are positioned by pressing a protrusion provided on the lid against a package inner wall.
The protrusion of the lid is provided with a curved surface through press molding and the inner diameter of the package is designed in such a way that the package inner diameter does not interfere with this curved surface. This causes a backlash between the package and the lid to increase, causing the lid to stick out of the package. To solve this problem, a technique is proposed which provides the package and the lid with height differences respectively to make the lid to fit into the package (e.g., see Japanese Patent Laid-Open No. 10-65036).